JPH0627374U - Automotive bumper - Google Patents

Abstract

(57) [Summary] [Object] To provide a resin-made bumper for an automobile, which can form the surface of the bumper body in a free shape, prevent sink marks on the surface of the bumper body, and ensure the strength of the reinforcing ribs. A resin bumper for an automobile having a bumper body 12 forming an outer surface of a vehicle body and a reinforcing rib 13 projecting from a back surface side of the bumper body 12, wherein the reinforcing rib 13 has the bumper A gas channel portion 13a having a cross-sectional shape larger than the general cross-section of the reinforcing rib 13 is formed at a position separated in the vicinity of the main body 12, and a hollow portion 13b is formed in the gas channel portion 13a. The connection portion 13c of the rib 13 between the gas channel portion 13a and the bumper body 12 is set to be thinner than the wall thickness of the bumper body 12.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a resin bumper for an automobile, and more particularly to a resin bumper having a reinforcing rib formed on the back side of a bumper body.

[0002]

[Prior art]

 2. Description of the Related Art In recent years, some automobile bumpers have been made of resin from the viewpoint of modeling and design, as shown in FIG. 3, for example. The resin bumper 1 is formed by integrally molding a bumper body 2 forming an outer surface of the vehicle body and a reinforcing rib 3 provided on the back surface side of the bumper body 2. The reinforcing rib 3 is provided so as to protrude along the substantially horizontal direction and is formed over substantially the entire width in the vehicle width direction. The reinforcing ribs 3 ensure the strength of the resin bumper 1 without increasing the weight so much.

However, if the reinforcing ribs 3 are formed on the back surface side of the bumper body 2 as described above, sink marks may be generated on the surface of the bumper body 2 and the appearance quality may be deteriorated. Was applied.

That is, as a first countermeasure, as shown in FIG. 4, a groove portion 2a is formed at a position corresponding to the reinforcing rib 3 on the surface side of the bumper body 2, and the groove portion 2a makes the sink mark inconspicuous. There is something like that.

As a second countermeasure, there is a method using a gas injection method. There is a resin bumper formed by using this method as shown in FIG. This is because a gas channel portion 3a is formed at the base of the reinforcing rib 3, the gas channel portion 3a is formed to have a larger cross-sectional shape than the general portion of the reinforcing rib 3, and a hollow portion 3b is formed inside. There is. In the molding of the resin bumper 1, the molten resin is injected into the cavity of the injection molding device, and at the same time as the injection is completed, gas is pressed into the gas channel portion 3a corresponding to the hollow portion 3b. As a result, the resin bumper 1 having the cross-sectional shape shown in FIG. 5 is molded.

At the time of this molding, a gas pressure is applied so that a holding pressure is applied from the inside of the resin in the cavity space by the gas pressure, so that the mold transfer property is improved, and the sink mark of the portion corresponding to the reinforcing rib 3 of the bumper main body 2 is improved. Is suppressed.

Further, as a third countermeasure, as shown in FIG. 6, the root of the reinforcing rib 3 is formed in a thin portion 3c thinner than other portions so that sink marks appearing on the surface of the bumper body 2 are made inconspicuous. Some have been proposed (see Japanese Utility Model Laid-Open No. 61-10259).

[0008]

[Problems to be solved by the device]

 However, in the first countermeasure shown in FIG. 4, it is necessary to form the groove portion 2a on the surface of the bumper body 2, and the bumper body 2 having no groove portion 2a and having a flat surface cannot be formed, which is a limitation in terms of molding. .

In the second countermeasure shown in FIG. 5, since the gas channel portion 3a is continuous with the bumper body 2, the size of the hollow portion 3b is smaller than that of the gas channel portion 3a, as shown in FIG. As described above, the sink mark 2b may be generated on the surface of the bumper body 2. The shape of the mold is larger than the shape of the finished product in consideration of the shrinkage amount of the resin material. Then, at the time of contraction, the bumper body 2 is deformed so as to have a large curvature. However, since the rigidity of this portion is improved by forming the gas channel portion 3a at the base of the reinforcing rib 3, the shape of the mold is maintained as compared with the other portions when contracting. As a result, the curvature of the other portion becomes large (see the chain double-dashed line in FIG. 5), while the curvature of the portion where the gas channel portion 3a is provided becomes small, which may impair the sense of continuity.

Further, in the third measure shown in FIG. 6, the strength is reduced by forming the thin portion 3c at the base of the reinforcing rib 3 for preventing sink marks.

Therefore, the present invention provides an automotive resin bumper that can form the bumper body surface in a free shape, can prevent sink marks on the bumper body surface, and can secure the strength of the reinforcing ribs. That is the issue.

[0012]

[Means for Solving the Problems]

 The present invention has been made in view of such a problem, and in a resin bumper for an automobile having a bumper body forming an outer surface of a vehicle body and a reinforcing rib projecting on the back side of the bumper body, In the reinforcing rib, a gas channel portion having a cross-sectional shape larger than a general cross-section of the reinforcing rib is formed at a position separated in the vicinity of the bumper body, and a hollow portion is formed in the gas channel portion, Further, the connecting portion of the reinforcing rib between the gas channel portion and the bumper body is an automotive resin bumper set to be thinner than the thickness of the bumper body.

[0013]

[Work]

 According to such a means, at the time of injection molding of the resin bumper, the generation of sink marks on the surface of the bumper main body is suppressed by the gas pressure injected into the portion corresponding to the hollow portion. Further, since the gas channel portion is separated from the bumper body, the sink mark as shown in FIG. 7 of the conventional example does not occur. Furthermore, by forming the connecting portion thinner than the bumper body, it is possible to further suppress the occurrence of sink marks.

Further, since the gas channel portion is separated from the bumper body, unlike the conventional case, the strength of the reinforcing rib forming portion of the bumper body does not become large unlike the conventional case. Therefore, when the bumper body contracts, its forming portion also deforms like other portions, so that the appearance quality is secured.

Further, unlike the prior art, it is not necessary to form a thin portion at the base of the reinforcing rib to prevent sink marks, and the connecting portion can be made thicker than the thin portion, so that the strength of the reinforcing rib and by extension the resin bumper is increased. Can be secured.

[0016]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 and FIG. 2 show an embodiment of the present invention.

First, the configuration will be described. In FIG. 1, reference numeral 11 is a resin bumper, and this bumper 11 has a bumper body 12 having a substantially U-shaped cross section and forming an outer surface of a vehicle body, and an inside of the body 12. The reinforcing ribs 13 projecting from the above are integrally formed.

The reinforcing rib 13 is provided so as to project from the vertical wall portion 12 a of the bumper body 12 in a substantially horizontal direction over substantially the entire width in the vehicle width direction. On the reinforcing ribs 13, gas channel portions 13a having a larger sectional shape than the general portion are formed so that the upper side thereof is convex at positions separated in the vicinity of the bumper body 12. A hollow portion 13b is formed in the gas channel portion 13a. Further, in the portion of the reinforcing rib 13 between the gas channel portion 13a and the bumper body 12 (hereinafter referred to as "connecting portion 13c"), the wall thickness T1 is formed thinner than the wall thickness T2 of the bumper body 12. . Further, the portion 13d of the reinforcing rib 13 on the tip side of the gas channel portion 13a is formed with a tapered surface 13e on the upper surface side so as to be tapered as it approaches the tip.

Next, a method of manufacturing the resin bumper 11 having such a configuration will be described.

The resin bumper 11 is manufactured using an injection molding apparatus as shown in FIG. This molding apparatus has a movable side mold 16 and a fixed side mold 17, and these molds 16 and 17 are matched with each other to form a cavity 18 for molding the resin bumper 11. There is.

A slide core 19 is slidably provided in the movable mold 16 in an oblique direction (arrow A direction), the slide core 19 is pushed out by the first ejector pin 20, and the second core 22 The ejector pin 21 is used to directly push out the bumper body 12. Further, a nozzle 22 into which gas is introduced is provided.

On the other hand, the fixed mold 17 is provided with a sprue 23 for injecting resin.

To mold the resin bumper 11 using such an injection molding apparatus, first, the two molds 16 and 17 are matched with each other, and the resin is injected into the cavity 18 through the sprue 23 and the runner 24. Simultaneously with the completion of the injection, the gas is pressed into the portion corresponding to the gas channel portion 13a (the portion indicated by the chain double-dashed line in FIG. 2) through the nozzle 22.

After that, in order to take out the molded product, both molds 16 and 17 are opened, the ejector plate 25 is moved in parallel to the left side in the drawing, and the slide core 19 is moved to the first position by the first ejector pin 20. 2 Press the molded product (resin bumper 11) directly with the ejector pin 21. As a result, the slide core 19 slides obliquely as shown by the arrow A, and is separated from the reinforcing rib 13 while pushing the molded product (resin bumper 11). In this case, since the tapered surface 13e is formed in the portion 13d on the tip side of the reinforcing rib 13, the releasability of the slide core 19 from the molded product (resin bumper 11) is improved.

As a result, the molded product (resin bumper 11) is released.

In the resin bumper 11 molded in this way, the generation of sink marks on the surface of the bumper body 12 is suppressed by the gas pressure that is pressed into the hollow portion 13b. Further, since the gas channel portion 13a is separated from the bumper body 12, sink marks do not occur as shown in FIG. 7 of the conventional example. Further, by forming the wall thickness T1 of the connecting portion 13c smaller than the wall thickness T2 of the bumper body 12, it is possible to further suppress the occurrence of sink marks.

Further, since the gas channel portion 13a is separated from the bumper body 12, the strength of the portion where the reinforcing rib 13 of the bumper body 12 is formed does not become large unlike the conventional case. Therefore, when the bumper main body 12 contracts, its forming portion is also deformed like other portions, so that the appearance quality is secured.

Further, unlike the conventional example shown in FIG. 6, it is not necessary to form the thin portion 3c at the base of the reinforcing rib 13 to prevent sink marks, and the connecting portion 13c can be thicker than the thin portion 3c. Therefore, it is possible to secure the strength of the reinforcing ribs 13 and thus the resin bumper 11.

[0030]

[Effect of device]

 As described above, according to the present invention, it is possible to prevent the occurrence of sink marks on the resin bumper and ensure the appearance quality, the strength of the resin bumper, and the deformation due to the contraction of the bumper body. Can be made the same in the part where the reinforcing ribs of the bumper body are provided and in the other parts as well, which also has a practical effect of ensuring the appearance quality.

[Brief description of drawings]

FIG. 1 is a sectional view taken along the vertical direction showing an embodiment of a resin bumper for an automobile of the present invention.

FIG. 2 is a cross-sectional view showing a molded state of an automobile resin bumper of the same embodiment.

FIG. 3 is a perspective view of a resin bumper for an automobile.

FIG. 4 is a sectional view corresponding to FIG. 1 showing a conventional example.

FIG. 5 is a sectional view corresponding to FIG. 1 showing another conventional example.

FIG. 6 is a cross-sectional view showing another conventional example.

FIG. 7 is a cross-sectional view showing another conventional example.

[Explanation of symbols]

 11 Resin bumper 12 Bumper body 13 Reinforcing rib 13a Gas channel section 13b Hollow section 13c Connection section

Claims (1)

[Scope of utility model registration request] 1. A resin bumper for an automobile, comprising: a bumper body forming an outer surface of a vehicle body; and a reinforcing rib projecting on a back surface side of the bumper body, wherein the reinforcing rib includes a bumper body of the bumper body. Gas channel portions having a cross-sectional shape larger than the general cross-section of the reinforcing ribs are formed at positions separated in the vicinity, hollow portions are formed in the gas channel portions, and the gas channel portions of the reinforcing ribs are further formed. A resin bumper for an automobile, characterized in that a connecting portion between the bumper body and the bumper body is thinner than a thickness of the bumper body.